1. Field of the Invention
The present invention relates to a semiconductor integrated circuit and an electronic device including the same. Specifically, the present invention relates to a semiconductor integrated circuit supplying a voltage to a load using a charge pump, as well as to an electronic device including the circuit.
2. Description of the Background Art
In a semiconductor integrated circuit using a charge pump, generally, a regulator is provided for changing an input voltage to the charge pump based on an output voltage of the charge pump, to keep the output voltage of the charge pump at a prescribed voltage.
In a conventional semiconductor integrated circuit using a charge pump, when a current supply to a load starts immediately after power-on of the semiconductor integrated circuit, a large current flows to the load instantaneously, causing malfunction of the circuit.
In order to solve such a problem, Japanese Patent Laying-Open No. 2005-33865 (Patent Document 1), for example, discloses a semiconductor integrated circuit in which a current flowing to an output terminal of a charge pump is detected by a sense resistor and a current detecting circuit, and a current limiting circuit is provided so that an input current of about twice the output current is kept flowing at an input terminal of the charge pump circuit, whereby the current is made constant, peak current is suppressed to prevent noise generation, and malfunction of other circuits connected to the same input power supply as the charge pump is prevented.
In the semiconductor integrated circuit described in Patent Document 1, however, as the sense resistor is arranged between the charge pump and the output terminal, the output voltage of semiconductor integrated circuit lowers in accordance with the output current. Therefore, it is necessary to increase the output voltage of the charge pump by the amount of voltage lowered by the sense resistor, which leads to undesirable increase of power consumption of the semiconductor integrated circuit. When a dynamic load is connected to an output of the semiconductor integrated circuit, namely, when a current flowing through the load varies, the output voltage of the semiconductor integrated circuit fluctuates, as the sense resistor is arranged between the charge pump and the output terminal.